1. Field of the Invention
This invention pertains to the field of alert signals being provided to the pilot of an aircraft, where such signals are generated by an airspace awareness and warning system.
2. Description of Related Art
Generally, an aviation regulatory authority or organization possesses the authority of designating and defining airspace. In the United States, the Federal Aviation Administration (“FAA”) establishes and provides the defined dimensions of airspace. Such airspace could be designated as regulatory and non-regulatory special use airspace, where regulatory special use airspace could include prohibited areas and restricted areas and non-regulatory special use airspace data could include military operations areas, alert areas, warning areas, and national security areas. Prohibited areas contain airspace of defined dimensions identified by an area within which the flight of aircraft is prohibited. Such areas are established for security or other reasons associated with the national welfare. Restricted areas contain airspace within which the flight of aircraft, while not wholly prohibited, is subject to restrictions. Activities within these areas must be confined because of their nature or limitations imposed upon aircraft operations that are not a part of those activities or both. Restricted areas denote the existence of unusual, often invisible, hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. Penetration of restricted areas without authorization from a using or controlling agency may be extremely hazardous to the aircraft and its occupants.
An airspace is invisible to the pilot but may be identified by a depiction on aeronautical charts or discussed in other publications which provide aeronautical information. The boundaries of an airspace may be delineated by vertical and horizontal limits. The vertical limits of airspace may be designated by altitude floors and ceilings expressed as flight levels or other appropriate measures such as feet or meters above mean sea level (MSL). The horizontal limits of an airspace may be measured and defined by geographic coordinates or other appropriate references that clearly define their perimeter. An airspace may be in effect for one or more designated time periods or run continuously.
The complexity with which an airspace is defined ranges considerably. On one side of the spectrum, the definition of the prohibited airspace of Washington, D.C. is highly complex, irregularly shaped, and defined, in part, by numerous physical landmarks and latitude/longitude points. On the other side of the spectrum, a restricted airspace of Flagstaff, Ariz. is relatively simple, cylindrically-shaped, and defined, in part, by a constant radius extending outward from the center of the airspace which is defined by a latitude/longitude point. In between, the restricted airspaces of Fort Sill, Okla. and Huntsville, Ala. are defined, in part, using four sets of latitude/longitude points. The definitions of each of these exemplary airspaces are presented and discussed below in detail.
Airspaces may present safety of flight issues to the pilot of an aircraft. A safety of flight issue could arise in the instance where a pilot's attention is diverted from flying the aircraft to looking down from the aircraft in an attempt to identify the physical landmarks that demarcate the boundaries of the complex Washington, D.C. airspace. Not only are the boundaries complex but the pilot could lose his or her focus on flying the aircraft and accidentally place the aircraft in an unsafe flight condition. Also, if the aircraft is flying in meteorological conditions that obscure the pilot's ability to see outside of the aircraft, a pilot may unknowingly and unintentionally penetrate such airspace; the same could occur during nighttime flight operations. Invisible hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles may be present, making the penetration of such airspace extremely hazardous to the aircraft and its occupants. Moreover, if a missile defense system is employed to protect the airspace from unauthorized intrusion, a pilot penetrating the airspace could experience tragic consequences should such system be activated and the missiles engage the aircraft.
The embodiments disclosed herein present novel and non-trivial systems and methods which address safety of flight issues related to accidental or inadvertent penetration of defined airspace.